Thomson Licensing

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Thomson Licensing S.a.

Interdigital Ce Patent Holdings

Ulrich Gries

Peter Georg Baum

Michael Arnold

Xiaoming Chen

Walter Voessing

Ulrich Schreiber

Peter Steinborn

Sven Kordon

Johannes Boehm

Xiao-Ming Chen

Achim Freimann

Jithin Zacharias

Markus Schneider

A method, a computer readable storage medium, and an apparatus for determining a target sound scene at a target position from two or more source sound scenes. A positioning unit positions spatial domain representations of the two or more source sound scenes in a virtual scene. These representations are represented by virtual loudspeaker positions. A projecting unit then obtains projected virtual loudspeaker positions of a spatial domain representation of the target sound scene by projecting the virtual loudspeaker positions of the two or more source sound scenes on a circle or a sphere around the target position.

Method, computer readable storage medium, and apparatus for determining a target sound scene at a target position from two or more source sound scenes

A challenge of audio watermarking systems in which an acoustic path is involved is the robustness against microphone pickup in case of surrounding noise. The strength of phase-based watermarking is increased by determining a masking threshold for a current frequency bin in a frequency/phase representation changing the phase based on that masking threshold and an allowed phase change value, calculating an allowed magnitude change value for the current frequency bin and calculating from an audio quality level value a magnitude change scaling factor for the magnitude change value, and increasing its magnitude accordingly.

Method and apparatus for increasing the strength of phase-based watermarking of an audio signal

Following transmission of a watermarked audio signal over an acoustic path causing echoes, reverberation and/or noise, watermark detection correlation result peak values are concentrated within a limited temporal range around main correlation result peaks, which limited temporal range is much smaller than the total correlation length. The watermark detection is based on the following: given ncorrelation result peak values v=(v, v, . . . , v) in an average or expected probability distribution for correlation result values for unmarked content, the probability is calculated that within windows covering the limited temporal range there are nor more values from a correlation result value set greater than or equal to these peaks v.

Method and apparatus for determining watermark symbols in a received audio signal that can contain echoes, reverberation and/or noise

Audio watermarking is the process of embedding watermark information items into an audio signal in an in-audible manner. In a first embodiment, in case the original audio signal has parts of low signal energy, an alternative signal having a level or strength given by the psycho-acoustic model is combined with the original audio signal. The combined signal is watermarked with watermark data to be embedded. In a second embodiment, in case the original audio signal has parts of low signal energy, an alternative signal having a level or strength given by the psycho-acoustic model is watermarked with watermark data to be embedded, and the audio signal is watermarked with the watermark data to be embedded. The watermarked alternative signal is combined with the watermarked audio signal.

Method and apparatus for watermarking successive sections of an audio signal

For watermark embedding, without full Dolby AC-3 decoding, mantissa bits in the AC-3 bit stream are changed by exploiting the fact that during AC-3 encoding more bits than required by the perceptual masking curve are used for the quantization of the MDCT coefficient mantissa values. In addition to the bap values, truly required bap values are determined and the mantissa values are changed accordingly, controlled by the watermark information. The advantages are efficient watermark embedding, other bit stream parameters and values remain unchanged except for CRC checks, and the audio quality of the watermarked signal remains perceptually unchanged.

Method and apparatus for watermarking an AC-3 encoded bit stream

Digital audio signal watermarking in real-time is difficult in an environment that has limited processing power. According to the invention, the channels in a data block-based audio multi-channel signal are prioritized with respect to watermarking importance, whereby the channel priority can change for different input signal data blocks. For a current input signal block, the most important channel is watermarked and the required processing time is determined. If this required processing time is shorter than a predefined application-dependent threshold, the next most important channel is marked and the additionally required processing time is determined, and so on. Due to the block-based nature of the audio watermarking including block overlap/add and due to the sensitivity of the resulting audio quality against blocking artifacts, several problems are solved in order to lead to acceptable performance and quality.

Method and apparatus for frequency domain watermark processing a multi-channel audio signal in real-time

Watermark symbol detection requires a detection metric for deciding at decoder side which candidate symbol is embedded inside the audio or video signal content. The invention provides an improved detection metric processing that achieves a reliable detection of watermarks in the presence of additional noise and echoes, and that is adaptive to signal reception conditions and requires a decreased computational power. This is performed by taking into account the information contained in the echoes of the received audio signal in the decision metric and comparing it with the corresponding metric obtained from decoding a non-marked audio signal, based on recursive calculation of false positive detection rates of peaks in correlation result values. The watermark symbol corresponding to the reference sequence having the lowest false positive error is selected as the embedded one.

Method and apparatus for detecting which one of symbols of watermark data is embedded in a received signal

The invention refers to a method for performing communication on a bus structured network between master device and slave devices using a bi-directional data stream DSA for secure communication and a unidirectional data stream DSI for real-time communication. According to the invention the unidirectional data stream DSI is used for a certain type of secure communication between a master device and at least one slave device.

Method and device for performing communication on a bus structured network

In watermarked signal decoding, the embedded message is decoded by correlating the reference patterns with the watermarked signal. The watermark detector decides, depending on the size of the correlation result values, whether or not a given reference pattern was embedded. However, decoding watermarked audio or video signals is difficult if the link between the watermark encoder and the watermark decoder is not a digital one, for example an acoustic path. A re-sampler control unit controls the sampling frequency of a re-sampler, in connection with a watermark decoder that outputs, in addition to the watermark information bits, a corresponding confidence value that is derived from the correlation result and that is used for synchronizing the re-sampler sampling frequency with the original sampling frequency of the watermarked signal. The synchronization processing includes a search mode and a synchronized mode.

Method and apparatus for determining and using the sampling frequency for decoding watermark information embedded in a received signal sampled with an original sampling frequency at encoder side

Many watermarking systems make use of correlation for calculating a detection metric, which means that several reference patterns are generated at encoder side and one or more of them are embedded inside the content signal, dependent on the message to be embedded. To decode the embedded message, it is necessary to discover which reference pattern was embedded at encoder side by correlating the known reference patterns with the content signal. In the case where watermarked audio is emitted by a loudspeaker and then captured with a microphone, the received signal echoes are used for watermark detection instead of treating them as noise by integrating the correlation values resulting from echoes into the main correlation peak, thereby using correlation result amplitude values located within a predetermined neighborhood of a correlation result peak amplitude value and exceeding a predetermined threshold.

Method and apparatus for determining whether or not a reference pattern is present in a received and possibly watermarked signal

The invention relates to the technical field of data transmission via a transmission link according to the TDM method, corresponding to time division multiplex. Such a method is used in an audio mixing console in order to transport the sample words of a plurality of audio channels jointly to an audio DSP processor and, after processing, to transmit them back from said processor to an output processor. Since the data output process is performed in an automated manner with the aid of a DMA unit, severe interfering noise can occur in cases of error, said noise also being output via the loudspeakers. The invention is based on the aim of avoiding such interfering effects. An error detection method based on the marking of data frames is used for this. For this purpose, a number of marking bits of the time slot of the data frame are set, the bit pattern of the marking bits being alternated in a defined sequence. Upon error detection, the outputting of the data via the loudspeakers is prevented, such that no interfering noise arises.

Data transmission method and device for carrying out the method

In audio processing technology there are interfaces of different type, the different interface types being associated with differing sample clock frequencies and/or differing data frame or data word formats. In some applications it is desired do process audio signals that stem from such interfaces of different type. According to the invention the input signals of the interfaces of different type are pre-processed for a subsequent common-format central processing, using a synchronization to the common system clock, channel decoding according to the differing channel protocols related to the different-type interfaces, and processing the resulting PCM bitstream format signals so as to form therefrom sample words that are stored in an intermediate store from which the sample words are fed to the central processing.

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Hannover, Germany

Ulrich Gries